This invention pertains to an upper head closure device for coking drums. It pertains particularly to such a closure device including a housing containing a rotatable ball valve and having a cover unit and rotatable cutting tool, all for attachment onto a coking drum upper head so as to permit convenient and safe coke drilling and removal from the drum.
Coking drums, from which coke deposited therein from coal or heavy hydrocarbon feedstocks must be removed periodically, usually require removal of an upper head flanged cover for insertion of tools for drilling or cutting the coke prior to its removal. However, this flange cover removal operation is somewhat hazardous to personnel because of escaping hot vapors and liquids from the drum. Currently, coking drums have a bolted blind flange cover that is manually removed for insertion of the coke drilling tools into the drum. During such operation, personnel removing the top flange cover are exposed to escaping hot vapors which may contain solids and/or liquids and is a serious problem. The present invention provides a closure device which obviates such hazardous removal of the upper flange cover during operation of coking drums.
Although the prior art has provided some valve type closure devices useful for gas supply systems from coking drums, none of these valve configurations are suitable for solving the present problem. For example, U.S. Pat. No. 4,797 to Chapman discloses a quick-opening manually-operated valve arrangement adapted for attachment onto gas supply systems. U.S. Pat. No. 1,517,786 to Kus discloses a curved gate valve for periodic closure of ascension pipes of a coking gas supply system. U.S. Pat. No. 1,580,323 to Paul discloses a valve configuration used on the upper end of a steam evaporator. U.S. Pat. No. 2,082,118 to Potter discloses a gas take-off valve configuration useful for withdrawing gas from coking drums. U.S. Pat. No. 2,603,232 to Keammerer discloses a rotary valve for coking gas supply systems, the valve utilizing a liquid seal and curved sealing surface. U.S. Pat. No. 3,858,609 to Stanke et al discloses a pivoted valve flap closure for use with the ascension pipe of a coke oven, which valve is operated by an external actuator. Also, U.S. Pat. No. 4,382,841 to Koddenberg discloses a coke gas conduit supply system which utilizes dual pivoted flapper valves operated in sequence. However, none of these known shut-off valve configurations for coking drums incorporate a rotary cutting or drilling tool which can be periodically extended downwardly through an open valve into a coking drum for loosening coke deposited in the drum, and thereby avoids periodic hazardous removal of an upper head flanged cover on the drum.